Facturación por error de un plan mensual

You can check the status of your plan, by going to https://account.adobe.com/plans. Chances are that as you got billed for the plan, it has not been cancelled. You should also check your e-mails, as Adobe sends an e-mail when a plan has been booked, together with the terms and conditions and when a plan got cancelled, to confirm that.

To cancel your stock subscription: Cancel your Adobe Stock membership 

To contact Adobe customer care: Adobe customer care can be contacted by beginning a secure chat session at https://helpx.adobe.com/contact.html?rghtup=autoOpen. Pop-up blockers need to be disabled! If the chat window fails to open, or is non-responsive, use a different device to start the interaction.
Support phone numbers may be found here: https://helpx.adobe.com/contact/phone.html. Please note that phone charges may apply.

For support via Twitter:
https://twitter.com/AdobeCare

(see also here: https://community.adobe.com/t5/creative-cloud-services/how-to-contact-adobe-support/td-p/11875703 or here
https://community.adobe.com/t5/account-payment-plan/how-to-contact-adobe-support/td-p/11843852)

Info on how to cancel your Stock subscription is shown in this Help page:

https://helpx.adobe.com/stock/kb/cancel-membership-subscription-stock.html